Effects of heat treatment and poly(vinylpyrrolidone) (PVP) polymer on electrocatalytic activity of polyhedral Pt nanoparticles towards their methanol oxidation

摘要

In this paper, the polyhedral Pt nanoparticles under control were prepared by polyol method using AgNO3 and poly(vinylpyrrolidone) (PVP) in the reduction of H2PtCl6 with ethylene glycol (EG). Transmission electron microscopy (TEM) and high resolution (HR) TEM measurements were used to investigate their characterization. In the case of the previous removal of PVP by washing and heating at 300°C, the specific morphologies of polyhedral Pt nanoparticles were still observed. However, the removal of PVP only by heat treatment at 300°C without washing causes the significant variation of their morphology. The large Pt particles were observed in the self-aggregation and assembly of the as-prepared polyhedral Pt nanoparticles. The pure Pt nanoparticles by washing and heat treatment showed the electrocatalytic property better than PVP-Pt nanoparticles by heat treatment due to the incomplete removal of PVP and by-products from AgNO3. Therefore, the removal modes of PVP without changing their characterization are required to obtain the good catalytic performance.